"I thought no one would take me but Richard Branson has offered me a seat on Virgin Galactic, and I said yes immediately."

Branson's spaceflight company hopes to send people to space on commercial missions. In 2015, he said Stephen Hawking was one of the people he "admired most in the world", adding he was the only person with a free ticket on board Virgin Galactic.

Professor Hawking also shared his views on US President Donald Trump during the interview.